Water tube boiler



Dec. l5, 1931. A. HUSTER l I WATER TUBE BoILER Filed Feb. 26. 1929 Patented Dec. 15, 1931 UNITED STATES PATENT OFFICE ALFRED H'U STER, 0F KIEL, GERMANY, ASSIGNOR T0 FRIED. KRUPP GERMANIAWERFT AKTIENGESELLSCHAFT, OF KIEL-GAARDEN, PRUSSIA, GERMANY WATER TUBE BoILER Application led February 26, 1929, Serial No. 342,802, and in Germany March 10, 19.28.

The invention relates to water tube boilers and has for its object an improved arrangement of the water tubes which immediately gre exposed to the heat radiated by the re- In various types of boilers such as upright water tube boilers and marine `boilers it is common to bend the tubes of several rows of water tubes so that all of these tubes will 1o lie in one plane and form a gas tight tube wall. In order to facilitate the bending of these tubes, they are made of a comparatively small diameter. If these tubes are directly eXposedto theheat radiated from the iirebox,

as is the case in modern boilers equipped with pulverized fuel burners, the permisslble length of these tubes is materially decreased, due to the fact that their small section of circulation renders them liable to overheating.

The invention has for its object to enable the use of these advantageous tube walls formed by uniting several tube rows in one plane, even with great heights of the firebox and correspondingly great length of the tubes. This object is obtained according to the invention by arranging in front of the tube wall, as a protection from the immediate heat radiation, at least one row of tubes which is composed of laterally spaced water tubes having a greater diameter than the tubes of the gas-tight tube wall.

In order to'allow of the invention to be more easily understood, an embodiment of same is illustrated by way of example in the accompanying drawings in which Figure 1 is a sectional view of a water tube boiler, and

Figure 2 is a fragmentary section on line II-II of Figure 1.

Referring to these figures, 1 denotes the upper drum and 2 the lower one of the boiler between which drums extends a nest of water tubes 3 the inner side of which is exposed to the heat radiation of the iirebox 4. In front of this nest of tubes 3 is arranged a protective tube wall 5 formed by three tube rows united in one plane and the length of the tubes of which is greater than it would be admissible with regard to their small diameter and due 50 to their being exposed immediately to the By the practice of this invention, a gastight tubewall can be arranged, formed by uniting in one plane several rows of smooth tubes, of small diameter. This may be done despite the fact that a irebox of great height is desired, resulting in a correspondingly greater length of water tubes, because the wall may effectively be protected from the intense heat radiation'from the lireboX.

I claim A In a water tube boiler of the class described a water tube wall composed of tubes of normal small diameter, and a plurality of rows of spaced water tubes arranged in staggered relation to one another in front of said tube-wall and consisting of tubes having a greater diameter than those of said tube wall, and arranged to exclude from said wall at least all direct radiation substantially normal to the plane of said Wall.

The foregoing specification signed at Hamthis 5th day of February,

burg, Germany,

DIPL. ING. ALFRED HUSTER. 

